Ecological Security Assessment On Grassland Using DPSIRM And SD Model

Xilin Gol Grassland is located in the middle part of Inner Mongolia;it’s not only the largest natural grassland of China,but also one of the important bases of animal husbandry.However,with the global warming,social and economic development and the enhancement of human activities lead to the grassland natural disasters occurred frequently,grassland degradation and desertification have become more serious.The degeneration of grassland has brought great loss and influence to the social economic development and human life in the pastoral area of our country and along with a series of problems in grassland ecological security.Therefore,this paper chose Xilin Gol as a case to research on the grassland ecological security assessment.Firstly,researched on the concepts of ecological security and the means of ecological security assessment and then construct a theoretical framework of grassland ecological secrutiy assessment.Secondly,by the means of system daynamic(SD)model to study the dynamic mechanism of the grassland ecological security system and diagnoze its influencing factors.Finally,based on multi-source data fusion(such as meteorological data,remote sensing data,social economic data and survey data etc.)and DPSIRM model to construct the assessment index system of grassland ecological security,and using the entropy weight method,comprehensive weighted evaluation method,grid GIS and optimum partition method to assessing and zoning the ecological security of Xilin Gol Grassland,and the results are as follows:(1)The system dynamics model of grassland ecological security including narual system,social system and economic system,and through the analysis on system structure and driving forces,we can conclude that the natural factors and human factors jointly drive the ecological security system of Xilin Gol grassland.And in natural facros such as drought and snow disaster are the main driving factors;in human factors,the pressure of population and economic growth on resource-environment is the key driving factor.(2)Based on assessment index system of grassland ecological security,using comprehensive weighted evaluation method and entropy weight method to dynamicly analyze the Xilin Gol grassland ecological security indexes such as driving force,pressure,state,impact,response and management,and the results show that the Xilin Gol were mainly dominated by medium driving force,medium-high and medium pressure,medium-high state,medium-low impact,medium-high response and medium management.(3)During the study period of 2005-2015,the ecological security level of Xilin Gol has an upward trend;specifically,the less-safe area decreases from 45500 km2 to 33500 km2,correspondingly the proportion decreased from 22.46% to 16.54%;the not-safe areadecreased from 19600 km2 to 11200 km2,which is tranfered into the general-safe and more-safe level.The spatial distribution of ecological security changing from west to east with a tendency of “not-safe→ less-safe→general-safe→more safe→total safe”,and this tendency was coincident with the spatial distribution of ecological security level,which means that the western part of Xilin Gol is facing the larger problem of ecological security,while the eastern part were relatively safe.